 /*******************************************************************************
  * Copyright (c) 2000, 2005 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.update.operations;

 import org.eclipse.core.runtime.*;
 import org.eclipse.update.configuration.*;
 import org.eclipse.update.core.*;

 /**
  * This class contains various validation methods to be invoked before or during executing update manager
  * operations.
  * <p>
  * <b>Note:</b> This class/interface is part of an interim API that is still under development and expected to
  * change significantly before reaching stability. It is being made available at this early stage to solicit feedback
  * from pioneering adopters on the understanding that any code that uses this API will almost certainly be broken
  * (repeatedly) as the API evolves.
  * </p>
  * @since 3.0
  */
 public interface IOperationValidator {

     /**
      * Called before performing install.
      * @return the error status, or null if no errors
      */
     public IStatus validatePendingInstall(IFeature oldFeature, IFeature newFeature);

     /**
      * Called before performing operation.
      * @return the error status, or null if no errors
      */
     public IStatus validatePendingConfig(IFeature feature);
     
     /**
      * Called before performing operation.
      * @return the error status, or null if no errors
      */
     public IStatus validatePendingUnconfig(IFeature feature);
     
     /**
      * Called before performing operation.
      * @return the error status, or null if no errors
      */
     public IStatus validatePendingReplaceVersion(IFeature feature, IFeature anotherFeature);
     
     /**
      * Called before doing a revert/ restore operation
      * @return the error status, or null if no errors
      */
     public IStatus validatePendingRevert(IInstallConfiguration config);

     /**
      * Called by the UI before doing a batched processing of
      * several pending changes.
      * @return the error status, or null if no errors
      */
     public IStatus validatePendingChanges(IInstallFeatureOperation[] jobs);

     /**
      * Check the current state.
      * @return the error status, or null if no errors
      */
     public IStatus validateCurrentState();
     
     /**
      * Checks if the platform configuration has been modified outside this program.
      * @return the error status, or null if no errors
      */
     public IStatus validatePlatformConfigValid();
 }

